Compares the two strings for lexicographical ordering. Returns non-nil if and only if x precedes y lexicographically. When non-nil, the number returned is the first position at which the strings differ.

Compares the two strings for lexicographical ordering. Returns non-nil if and only if x precedes y lexicographically. If they differ, the number returned is the first position at which the strings differ. Otherwise, the number returned is their common length.

Compares the two strings for lexicographical ordering. Returns non-nil if and only if y precedes x lexicographically. When non-nil, the number returned is the first position at which the strings differ.

Compares the two strings for lexicographical ordering. Returns non-nil if and only if y precedes x lexicographically. If they differ, the number returned is the first position at which the strings differ. Otherwise, the number returned is their common length.